Method and apparatus for forming radius corners

ABSTRACT

According to the preferred embodiment of the present invention, a method for forming radius corners from bulkstock is disclosed. The method comprises the step of disposing the bulkstock in a first fixture for securing said bulkstock. A first general radial exterior surface is then formed. The bulkstock is then disposed in a second fixture for securing the bulkstock. Finally, a second generally radial posterior surface is formed on the bulkstock. Additional fixtures which are disclosed wherein may also be used.

This is a continuation of U.S. patent application Ser. No. 649,023,filed Feb. 1, 1991 entitled; METHOD AND APPARATUS FOR FORMING RADIUSCORNERS which issued Oct. 22, 1991 as U.S. Pat. No. 5,058,640, which isa continuation now U.S. Pat. No. 5,002,107 issued Mar. 26, 1991.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the fabrication of furniture and the like, andmore particularly concerns the method and apparatus for performingradius corners.

2. Description of the Related Art

In the manufacture of furniture such as tables, countertops and othersimilar items, it is often desirable to place moldings around the edgesof a generally planar surface. The purpose of such moldings is to coverthe edges of the base material of the table which may be a compositionboard material. In addition, such moldings often improve the wearresistance of the table, as well as enhance the aesthetic appearance ofthe table.

When moldings are used in this manner, it is often necessary tofabricate radius corners which are able to accommodate the corners ofthe table. However, the formation of such radius corners is often verydifficult. One method for forming radius corners is to first cut a pieceof bulkstock to the general shape of the corner of the table top, andthen sequentially sand and measure the radius corner until a proper fitis attained. Another method for forming a radius corner is to first formthe inside surface of the radius corner and then attach the insidesurface of the bulkstock to the corner of the table by means of anadhesive. Once the adhesive has hardened, the bulkstock may be machinedsanded and finished to match the remainder of the molding which will beused to form the table.

While the method described above have been generally successful informing radius corners, they often have several disadvantages. First,such methods for forming radius corners are often time consuming,requiring the craftsman to spend a substantial amount of time in machineset-up, shaping, sanding and then trimming the radius corner to get theproper fit. This procedure becomes even more difficult when the radiuscorner is to match profiled linear molding having a bullnose, bevelgroove which can eventually contain decorative strip. Furthermore, ifthe bulkstock were first attached to the corner of the table beforemachining the profile, the entire table would generally have to be movedso that a profile could be formed on the exterior surface of the radiuscorner, or machined with a portable router with bearing guide tooling orspecial fixturing to guide the router. This could also limit theaccuracy of the radius corner profile to the linear molding by use ofstandard router bits available.

SUMMARY OF THE INVENTION

According to the preferred embodiment of the present invention, a methodfor forming radius corners from bulkstock is disclosed. The methodcomprises the step of disposing the bulkstock in a first fixture forsecuring said bulkstock. A first general radial exterior surface is thenformed. The bulkstock is then disposed in a second fixture for securingthe bulkstock. Finally, a second generally radial posterior surface isformed on the bulkstock. Additional fixtures which are disclosed hereinmay also be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Various advantages of the present invention will become apparent to oneskilled in the art upon reading the following specification andreference to the following drawings in which:

FIG. 1a is a perspective view, as well as a cross-sectional view, of theradius corner formed according to the preferred embodiment of thepresent invention;

FIG. 1b is a cross-sectional view of the corner molding shown in FIG.1a;

FIG. 2 is a perspective view of the bulkstock which is used to form theradius corner;

FIG. 3a is a perspective view of a first fixture for securing thebulkstock when the outside radius of the bulkstock is cut;

FIG. 3b is a view of the underside of the fixture shown in FIG. 3a;

FIG. 4 is a perspective view of fixture shown in FIG. 3 which allowsformation of a face profile on the bulkstock.

FIG. 5a is a perspective view of a fixture for cutting the inside radiusof the bulkstock;

FIG. 5b is an elevational view of the bottom of the fixture shown inFIG. 5a;

FIG. 6 is a perspective view of a fixture for securing the bulkstockwhile the inside radius of the bulkstock is being finished; and

FIG. 7 is a perspective view of the fixture for forming 90° angles onthe bulkstock.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a table is shown which is generally designated bythe numeral 10. The table 10 may have a top surface 12 which is wood,though it may also have a surface which is laminated to a base material.Disposed along the periphery of the table are two linear moldingsections 14 and 16 as well as a radius corner molding 18. The linearmolding sections 14 and 16 and the radius corner molding 18 are used toenhance the appearance of the table 10 as well as to improve the wearcharacteristics of the table 10. While the present invention has beendescribed with reference to a table, it will be understood that thepresent invention may also be used with other similar surfaces such asdrafting tables, countertops, doors, and so forth.

Disposed along the longitudinal periphery of the linear molding sections14 and 16 as well as the radius corner molding 18 is a longitudinalgroove 20. The longitudinal groove 20 may be used to secure decorativemolding strips which also enhance the attractiveness of the table 10.The cross-section of the linear molding sections 14 and 16 as well asthe radius corner molding 18 is essentially semicircular. That is, theradius corner molding 18 has a general circular anterior surface 22 aswell as a relatively planar posterior surface 24. It is to beunderstood, however, that other suitable cross-sections may be used. Thelinear molding sections 14 and 16 and the radius corner molding 18 maybe secured to the table 10 in suitable manner such as by the use of anadhesive. In addition, the posterior surface 24 of the radius cornermolding 18 may have a projection (not shown) which is operable to engagea groove in the table.

The radius corners similar to radius corner molding 18 have beendifficult to mass produce because of the difficulty in securingbulkstock from which it is made during manufacture. The term "bulkstock"is meant to include wood, solid surfacing material such as CORIAN orFOUNTAIN HEAD, or other suitable materials, Accordingly, radius cornermoldings similar to the radius corner molding 18 were generally formedby securing the bulkstock to the corner of the table and then formingthe cross-sectional surface of the corner radius molding. Because radiuscorner moldings could not generally be formed without being secured tothe table with which it was to be used, it was not generally possible topremanufacture radius corner moldings in large quantities.

In contrast, the present invention allows for the premanufacture ofradius corner moldings in relatively large quantities. This is madepossible by the method disclosed herein which permits bulkstock to besecured during machining.

According to the present invention, a bulkstock is used which isgenerally designated by the numeral 26. The bulkstock 26 has a firstsurface 28 which will be shaped into the first anterior radial surface22 of the radius corner molding 18, and has a second surface 30 whichwill be shaped to form the second posterior radial surface 24 of theradius corner molding 18. In addition, the bulkstock has third andfourth surfaces 32 and 34 which each have a 45°×15° compound angle. Thatis, the compound angle is 45° from the first surface 28 and is 15°between the upper surface 36 and the lower surface 38 of the bulkstock26. It is to be understood, however, that other compound angles may beused.

To provide first means for securing the bulkstock 26 when the firstsurface 28 is being cut, a fixture 40 is provided as shown in FIG. 3.The fixture 40 is generally rectangular in shape and may be formed fromeither wood, aluminum, steel or other suitable materials.

The fixture 40 includes a back support surface 42 which extendsapproximately half way through the thickness of the fixture 40, therebyforming a recess 44 which is operable to engage the bulkstock 26.Connecting the back support surface 42 of the fixture 40 to theperimeter of the fixture 40 are the angular side support surfaces 46 and48. The angular side support surfaces 46 and 48 extend from the backsupport surface 42 to the perimeter of the fixture 40 and are angulatedin a manner so as to correspond to the compound angles in the third andfourth surfaces 32 and 34 of the bulkstock 26. In addition, the backsupport surface 42 is also connected to the bottom support surface 50which contains an abrasive non-slip surface 52 to assist in stabilizingthe bulkstock 26 when the bulkstock 26 is disposed within the recess 44.

The recess 44 of the fixture 40 is able to engage the bulkstock 26 inthe following manner. The first angular side support surface 46 of thefixture 40 engages the fourth surface 34 of the bulkstock 26, while thesecond angular side support surface 48 engages the third surface 32 ofthe bulkstock 26. When the bulkstock 26 is disposed within the recess 44of the fixture 40, it is automatically centered by compound angles andthen may be secured within the recess 44 by a clamp 54. The clamp 54 maybe Destaco part number 207 or 207UL, though other suitable clamps may beused. In addition, more than one clamp 54 may be used if additionalsupport is necessary.

The fixture 40 has a radial perimeter section 56 and a locating hole 58shown in FIG. 3b. The locating hole 58 is used to engage a pin (notshown) which is on the table of a bandsaw or suitable device so as toallow the fixture 40 to rotate. Accordingly, upon rotation of thefixture 40, the first surface of the bulkstock can be radially cut. Theradial perimeter section 56 allows for this rotational movement of thefixture 40 without damage to the fixture 40. A shaper or an overheadrouter may then be used to form the first anterior radial surface 22 ofthe corner radius 18 while the bulkstock 26 is being held in the fixture40 or in a fixture similar to the fixture 40. This is shown in FIG. 4.In the typical manufacturing environment, however, two of the fixtures40 will be used.

After a radial cut has been made in the first surface 28 of thebulkstock 26 and has been finished by a shaper, the bulkstock 26 isremoved from the first fixture 40 and then secured to a second fixturewhich is generally designated by the numeral 60 in FIG. 5. The fixture60 is similar to the fixture 40, and similar elements have ben given thesame number as that appearing in FIG. 4 with respect to the fixture 40,but having a suffix "a" in addition. In contrast, however, the distancebetween the radial perimeter section 56a and the back support surface42a of the fixture 60 is less than that associated with the fixture 40so as to permit a greater amount of the bulkstock 26 to overhand therecess 44a. Once the bulkstock 26 is secure within the fixture 60, thefixture 60 may be rotatably placed on a bandsaw table so as to but thatportion of the bulkstock 26 that is overhanging the radial perimetersection 56a to form roughly the posterior radial surface of the radiuscorner molding 18.

To smooth the posterior radial surface 24 of the radius corner molding18, a third fixture 62 is used as shown in FIG. 6. The fixture 62 has agenerally rectangular base with a horseshoe-shaped recess 64. Thehorseshoe-shaped recess 64 comprises a groove 66 which is semicircularin cross-section and is able to accommodate the machined first surface28 the bulkstock 26. In addition, the fixture 62 may have a top layerwhich is formed from a transparent material such as Plexiglas tofacilitate viewing the bulkstock 26 during manufacturing.

To secure the bulkstock 26 within the groove 66, a clamp 68 is used. Theclamp 68 applies a force against the fourth surface 32 of the bulkstock26 so as to force the third surface 34 against an angulated grooveterminating surface 70 in the groove. The groove terminating surface 70is angulated so as to engage the compound angle associated with thethird surface 34 of said bulkstock 26. In addition, a clamp 68 isdisposed perpendicularly to the fourth surface 36 of the bulkstock 26 soas to secure the bulkstock within the groove 66. While the clamp 68 maybe Destaco Model No. 603, other suitable clamps may be used.

Once the bulkstock 26 is secured in the fixture 62, the fixture 62 maybe rotated around a shaper or an overhead router (not shown) so as toshape the second surface 30 of the bulkstock 26 to form the posteriorradial surface 24 of the radius corner molding 18. In doing so, abearing guide (not shown) may be used so as to locate the shaper cutterwith respect to the fixture 62.

After the second surface 30 of the bulkstock 26 is shaped to form theposterior radial surface 24 of the radius corner molding 18, the thirdand fourth surfaces 32 and 34 of the bulkstock 26 have to be cut so thatthey will become perpendicular to each other and are therefore able tomate with the linear molding sections 14 and 16. To cut the third andfourth surfaces 32 and 34 of the bulkstock perpendicularly, the fixture72 shown in FIG. 7 may be used. The fixture 72 comprises a bulkstocksupport member 73 having an arcuate surface 74 which is able to engagethe second surface 30 of the bulkstock 26. Disposed on the bulkstocksupport member 73 is a first clamp 77 which is able to downwardly securethe bulkstock 26 when placed against the arcuate surface 74 of thesupport member 72. While the first clamp 76 may be a Destaco part No.207 or 207UL, other suitable clamps may be used.

The fixture 72 also comprises a second clamp 78 which is used to exert aforce against the first surface 28 of the bulkstock 26 so as to forcethe bulkstock 26 against the arcuate surface 74 of the bulkstock supportmember 73. The third surface 32 of the bulkstock 26 is then trimmed bymeans of a saw 76 which is perpendicular to a first planar surface 78 ofthe support member 73. The bulkstock 26 is then rotated 180° so as toallow the saw 76 to cut the fourth surface 34 of the bulkstock 26.

The fixture 72 also comprises a wedge 80 and a wedge support member 82.When the wedge 80 and wedge support member 82 are disposed against asecond planar surface 84 of the bulkstock support member 73, the fourthsurface 34 of the bulkstock 26 may be cut in the desired manner. It willbe noted that the bulkstock 26 is placed adjacent to the wedge 80 onlywhen the fourth surface 34 of the bulkstock 26 is being cut.

The entire process of forming the radius corner molding 18 will now bedescribed. The bulkstock 26 is first formed with the third and fourthsurfaces 32 and 34 having compound angles as shown in FIG. 2. Thebulkstock 26 is then inserted into the fixture 40 so that the secondsurface 30 is adjacent to the back support surface 42 of the fixture 40,while the third and fourth surfaces 32 and 34 of the bulkstock 26 aredisposed against the second and first angular side support surfaces 48and 46 of the fixture 40, respectively. The clamp 54 is then positionedso as to secure the bulkstock 26 within the fixture 40. The fixture 40is then rotated on a bandsaw table (not shown) so as to form a radialsurface on the first surface 28 of the bulkstock 26.

The bulkstock 26 is then removed from the fixture 40 and thentransported to another fixture which is substantially identical to thefixture 40. A shaper or router is then used to shape the first surface28 of the bulkstock 26 to form what will become the profile of theanterior surface 22 of the radius corner molding 18.

The bulkstock 26 is then removed and placed in the fixture 60 in amanner similar to that which was described above in connection with useof the fixture 40. A bandsaw is then used to cut through the uppersurface 36 of the bulkstock 26 so as to form a radial surface on thefirst surface 28 of the bulkstock 26. The bulkstock 26 is then removedfrom the fixture 60 and placed in the fixture 62 with the first surface28 of the bulkstock 26 disposed adjacent to the groove 66, as well ashaving the third surface 32 of the bulkstock adjacent to the grooveterminating surface 70. The clamp 68 is then used to secure thebulkstock 26 within the groove 66, and then a shaper (not shown) with abearing guide may be used to finish the second surface 30 so as to formthe posterior surface 24 of the radius corner molding 18. The bulkstock26 is then removed from the fixture 62 and placed in the fixture 72,with the second surface 30 of the bulkstock 26 adjacent to the arcuatesurface 674 of the bulkstock support member 763. The clamp 77 thenengages the first surface 28 of the bulkstock 26 so as to stabilize thebulkstock 26 when the fourth surface 34 of the bulkstock is cut by thesaw 76. The clamp 77 is then released, the bulkstock rotated 180°, thewedge 80 inserted between the bulkstock support member 73 and thesupport member 82 and then the saw 76 is used to cut the third surface32 of the bulkstock. By cutting the first and second surfaces 28 and 30in this manner, the first and second surfaces 28 and 30 will becomeperpendicular.

It should be understood that the invention has been described inconnection with a particular example thereof. Other examples willinclude various modifications to the structure described above includingreplacement of the clamps by hydraulic clamps, as well as the use ofrobotics. Other modifications will become apparent to those skilled inthe art after a study of the specification, drawing and followingclaims.

What is claimed is:
 1. A radius corner formed from bulkstock havingfirst and second surfaces by a process comprising the steps of:disposingsaid bulkstock in a first means for securing said bulkstock; forming afirst generally radial surface on the first surface of said bulkstock;removing said bulkstock from said first means for securing saidbulkstock; disposing said bulkstock in a second means for securing saidbulkstock; and forming a second generally radial profile surface on thesecond surface of said bulkstock.
 2. The radius corner formed by theprocess of claim 1 wherein said bulkstock has third and fourth surfaces,said process further comprising the step of forming a compound angle onthe third and fourth surfaces of said bulkstock.
 3. The radius cornerformed by the process of claim 2 wherein said first means for securingsaid bulkstock includes a back support surface and first and secondangular side support surfaces, said back support surface operable tosupport the second surface of said bulkstock while said first and secondangular side support surfaces are operable to engage the third andfourth surfaces of said bulkstock.
 4. The radius corner formed by theprocess of claim 3 wherein the step of forming a first generally radialsurface on the first surface of said bulkstock includes the step ofrotating said first means for securing said bulkstock.
 5. The radiuscorner formed by the process of claim 4 wherein said second means forsecuring said bulkstock includes the back support surface as well asfirst and second angular side support surfaces, the step of disposingsaid bulkstock in said second means for securing said bulkstock includesthe step of causing the third and fourth surfaces of the bulkstock tosubstantially engage the first and second angular side support surfacesof said second means for securing said bulkstock.
 6. The radius cornerformed by the process of claim 5 wherein the step of forming a secondradial surface on said bulkstock includes the step of rotating thesecond means for supporting said bulkstock.
 7. The radius corner formedby the process of claim 6 wherein the step of forming a second generallyradial surface includes the step of disposing said bulkstock in a thirdmeans for supporting said bulkstock.
 8. The radius corner formed by theprocess of claim 7 wherein the third means for supporting said bulkstockincludes a generally radial groove, and wherein the step of disposingsaid bulkstock in the third means for supporting said bulkstock includesthe step of disposing said first surface of said bulkstock within theradial groove.
 9. The radius corner formed by the process of claim 8wherein the bulkstock includes third and fourth surfaces, at least oneof the third and fourth surfaces has a compound angle, and wherein thestep of disposing said bulkstock in said radial groove includes the stepof causing the compound angle of said bulkstock to engage an angulatedgroove terminating surface disposed within said radial groove.
 10. Theradius corner formed by the process of claim 7 wherein said bulkstockincludes third and fourth surfaces, and wherein the process furthercomprises the step of perpendicularly cutting the third and fourthsurfaces of said bulkstock by disposing said bulkstock adjacentgenerally arcuate support surfaces so as to position said bulkstock withrespect to a cutting member.
 11. A fixture for positioning andsupporting bulkstock during the formation of radius corner moldings,said bulkstock including first, second, third, fourth, fifth and sixthsurfaces, said fixture comprising:a front surface formed in apredetermined radius configuration; and a recess formed in said fixture,said recess being operable to accept said bulkstock, wherein said recessis open to a top surface of said fixture and to said front surface. 12.The fixture according to claim 11 wherein said recess includes a firstside support surface and a second side support surface configured atcompound angles relative to a bottom support surface of said recess,said first side support surface operable to engage said third surface ofsaid bulkstock and said second side support surface operable to engagesaid fourth side surface of said bulkstock, said fifth surface of saidbulkstock slidable along and supportable by the bottom support surfaceof said recess.
 13. The fixture according to claim 11 further comprisingmeans for allowing said fixture to rotate about a preselected point. 14.The fixture according to claim 11 wherein said recess is configured suchthat an anterior surface of the radius corner molding can be machinedrelative to the front surface when the second surface of said bulkstockis engaged with a back support surface of the recess.
 15. The fixtureaccording to claim 11 wherein said recess is configured such that aposterior surface of the radius corner molding can be machined relativeto the front surface when the second surface of said bulkstock isengaged with a back support surface of the recess.
 16. A method forforming radius corners from bulkstock having first and second surfaces,said method comprising the steps of:positioning said bulkstock in afirst means for securing said bulkstock; forming a first generallyradial profile surface on the first surface of said bulkstock; andpositioning said bulkstock in a second means for securing saidbulkstock.
 17. The method of claim 16 wherein the step of positioningsaid bulkstock in a first means for securing includes positioning thefirst surface of the bulkstock against a back support surface associatedwith the first means for securing and positioning third and fourthsurfaces of the bulkstock against opposite side support surfacesassociated with the first means for securing, wherein the opposite sidesupport surfaces of the first means for securing are at a predeterminedangle relative to a bottom support surface of the first means forsecuring.
 18. The method according to claim 17 wherein the step offorming a first generally radial surface includes rotating the firstmeans for securing such that the radial profile is formed by a cutthrough the bulkstock following a generally radial profile of a frontsurface of the first means for securing.
 19. The method according toclaim 16 wherein the step of positioning said bulkstock in a secondmeans for securing includes the steps of positioning the second surfaceof the bulkstock in a generally radial groove associated with the secondmeans for securing and positioning a third surface of the bulkstockagainst a support surface within the groove.
 20. The method according toclaim 16 further comprising the steps of positioning said bulkstock in athird means for securing said bulkstock, wherein third and fourthsurfaces of said bulkstock are disposed adjacent generally arcuatesupport surface so as to position said bulkstock with respect to acutting member.